This section is intended to provide a background or context to the exemplary and non-limiting embodiments of this invention that are recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this invention.
In wireless communication, different collections of communication protocols are available to provide different types of services and capabilities. The long term evolution (LTE) is one of such collection of wireless communication protocols that extends and improves the performance of existing UMTS (universal mobile telecommunications system) protocols and is specified by different releases of the standard by the 3rd generation partnership project (3GPP) in the area of mobile network technology.
Of interest herein are the further releases of 3GPP LTE targeted towards future international mobile telephony-advanced (IMT-A) systems, referred to herein for convenience simply as LTE-Advanced (LTE-A). A goal of LTE-A is to provide significantly enhanced services by means of higher data rates and lower latency with reduced cost. LTE-A is directed toward extending and optimizing the current 3GPP LTE radio access technologies to provide higher data rates at very low cost. LTE-A will be a more optimized radio system fulfilling the international telecommunication union radiocommunication sector (ITU-R) requirements for IMT-A while maintaining backward compatibility with the current LTE release.
Both time-division duplexing (TDD) and frequency-division duplexing (FDD) schemes are adopted in LTE. In LTE TDD scheme, the downlink (DL) transmission (from the network to the user equipment) and the uplink (UL) transmission (from the user equipment to the network) are operated at the same carrier frequency, but are allocated to different time portions, or the so-called subframes. In LTE-A, several UL/DL subframe configurations are available for semistatic selection according to the ratio of UL and DL data. Recently, dynamic allocation of subframes to UL or DL is considered.
The concept of a heterogeneous network has attracted considerable attention to optimizing performance, particularly for unequal user or traffic distribution. In a heterogeneous network, different layers of cells are deployed in a less well planned or even uncoordinated manner. To combat with the challenge of interference management, different inter-cell interference coordination (ICIC) technologies are studied, one of which is the time domain (TDM) ICIC. The general description of TDM ICIC can be found in 3GPP, “TS 36.300 Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2”, v10.5.0 (2011 September), subclause 16.1.5, attached as Appendix A. In TDM ICIC, interference coordination is based on muting subframes. The muting is accomplished by using almost blank subframes (ABS) or multimedia broadcast multicast service single frequency network (MBSFN) subframes with a periodic pattern. Almost blank subframes are subframes with reduced transmit power, including no transmission, on some physical channels and/or reduced activity. TDM ICIC is mainly aimed for interference scenarios between macro evolved NodeB (eNodeB or eNB) and CSG (closed subscriber group) home eNode B (HeNB), and between macro eNodeB and pico eNodeB, but the muted subframes could be used for HeNB-HeNB interference management purposes as well.